To Rebuild the Heart I Lost
by Borlaaq
Summary: The Hollow Knight had been locked up for so long, mentally and physically. Grimm will tear off their chains one by one. Grimm/The Hollow Knight PWP


Can I tell you something just between you and me?

When I hear your voice, I know I'm finally free.

**-Here With Me by Marshmello**

The Hollow Knight's wounds take a long time to heal and Hornet often leaves Grimm in charge of helping them while she deals with the politics surrounding their lives. The Hollow Knight in general doesn't often let anyone close to them, let alone allow anyone to touch them. They flinch and bare their claws often, nearly feral after years in chains. Grimm is one of the few they allow close. They remember Grimm from before and Grimm had been a comfort to them even then.

But that's not to say they still aren't afraid. All their life, every touch led to pain. Understanding that touch didn't always equate to pain is a lesson they are still learning. Along with emotions in general. The Hollow Knight had been locked up for so long, mentally and physically. Grimm will tear off their chains one by one.

"Your sister is busy so I'll be helping with your wounds today," Grimm says softly. It's only been a few months since everything happened. There is no pain in his missing eye, but that will never be true for the Hollow Knight. Even with all his memories back, Grimm is still young, having not yet gone through his final molt. He is awkward in this state, still using his tail for balance, with too long limbs and his wings still too big to look like a natural cape.

The Hollow Knight nods at him stiffly, still learning to be comfortable with the movement.

"We can go to the hotspring. It will help much more than the ointments," Grimm flashes his fangs. That draws a more enthusiastic nod from them. Grimm dislikes water most of the time but he knows they love the soothing heat of the springs. He watches them stand up, using their nail to help make up for their missing arm and the offset of balance it made. Grimm wants to help them but holds himself back. The spring is just down the stairs.

When they join his side and they start to make the walk to the hot springs, Grimm says, "Do you remember what I called you when you were young?"

The Hollow Knight has to think about it. Grimm and their father often fought behind closed doors and when Grimm came out, his eyes were sad. He would kneel down and say, 'The Wyrm is selfish to think he can make an Ambrosia of you. I am sorry for it all.'

They nod and Grimm smiles, honestly, "You were made as nothing but a meal for my sister, but how funny that you've now become my closest friend." They are at the springs now and Grimm holds out his hand to take their cloak as they remove it. "Against all odds, you survived, Ambrosia. And I am so proud of you."

The sentence makes the Hollow Knight shake. They had long tried to get their father to say the same thing, but never heard it. Hearing Grimm say it made them feel warm. Having Grimm give them a name made them feel almost too hot. It's personal and Grimm only ever uses it when they are alone. They wonder if maybe they could get Hornet and Ghost to call them it too.

Grimm watches them slowly ease into the water before he joins them. He sits next to them but gives enough space between them. Their carapace is healing well enough, jagged cracks still occasionally ooze void and the stump of their arm is useless. He doesn't know if vessels are capable of growing limbs back like some other bugs, but he knows that if they really missed it, they could form another out of void. Grimm, however, knows the Hollow Knight hates to be reminded of what they are – they want to be normal so badly.

"I'm going to clean your side now," he says to give them plenty of time to prepare for the touch. They stiffen but also give a nod. Grimm wrings out the cloth he had brought and slowly works on cleaning up the dried void around the cracks. Some are still pretty deep but others are starting to scar over, leaving lighter reminders across their shell. The Hollow Knight winces at the touch and Grimm coos softly to them, using his magic to heat the cloth slightly to help with the pain.

They seem to like the heat, leaning into it slightly. He chuckles quietly, heating up his other hand to smooth down some of the jagged pieces of their carapace. The heat helps him push it down softly. They lean closer.

"Are you cold, my friend?" He asks. Their body temperature had drastically lowered the water temperature already. They don't reply, instead opting to look away. Grimm knows they don't like to see their wound but there is a form of embarrassment in the action. They are mostly clean, so instead Grimm lowers his hands to the water. The Hollow Knight turns their gaze to watch. He heats the water with his magic, it starting to steam and bubble around him and spread out. He feels the Hollow Knight rumble, rather than hears it. "Do you like that?"

Grimm can't help but smile honestly; he's never seen them do that. They nod, leaning their snout down to press against the bubbles. Grimm's heart skips a beat. As the bubbling dies down, they pull their head from the water, shaking off the liquid and preparing to stand. "We have to wash the rest of you, you know."

They all but collapse back into the water with a splash, making Grimm have to spit out water with narrowed eyes. He swears the Hollow Knight looks almost smug. Grimm huffs, moving back towards them to clean the lower part of the wounds. The cracks in their shell extend almost completely down their side, even past their hips and Grimm finds his brows drawn together as he works on cleaning them. How could someone do this to them? He swallows. How could _his sister_ do this to someone?

"I'm sorry…" He hadn't mean to say it aloud but the Hollow Knight shifts to look down at him. He runs his claws across the scars carefully as he decides to continue, "I...didn't help you. I knew your father's plan and I didn't stop him. I didn't even stop my own kin from hurting you. My own sister." He clenches his jaw, trying to calm the sudden anger growing in his gut.

The Hollow Knight suddenly tugs him close, into a tight and awkward hug. They squeeze him roughly, smothering him against their chest. Grimm can't help but chuckle, pushing back slightly so he can at least breathe. "No, no, no. That's a terrible hug!" Grimm shuffles, helping them put their arm around his shoulders correctly and he loops his own arms around their waist. "Now you squeeze. Gently, though." They nod and obey, leaning down to nuzzle his head. Grimm sighs, hugging back. "There you go…" His voice trails off as he leans his head onto their shoulder. His hands trace distracted patterns on their back and they attempt to copy the action. He starts to purr before cutting himself off pulling back slightly, "We should finish up." They shake their head suddenly and Grimm raises a brow. "No?"

They struggle for a moment, unsure how to express themselves before slipping a hand under Grimm's cape and writing a word with their finger on his back. '_Warm_' and then after another pause, '_Nice_'. The action takes him by surprise and he nearly melts at the words.

"We...can stay like this, then," Grimm says, "But don't tell your sister I'm slacking!" He chuckles at his own joke and the same rumbling comes from the Hollow Knight. A laugh, perhaps? Grimm is still learning their tells. He rubs their back they pull him closer. It's an awkward position, with them sitting next to each other and Grimm shifts to try and find a better way to keep close. They beat him to it, though, by tugging him into their lap. A small surprised noise leaves him and he presses his face to their shoulder again to hide his blush.

'_Warmer?_' They even punctuate the question by drawing on his lower back. It takes Grimm a moment for him to realize they're asking _why_ he's warmer.

"Ah. Oh. This...position is...intimate…" he mumbles.

The Hollow Knight instantly jerks back, tense and afraid they had overstepped. They try to untangle themself but Grimm puts a hand on their cheek firmly. "If it doesn't bother you, I am fine."

They meet his gaze, head cocked to the side and slowly reach their hand up to mimic Grimm's action on his cheek. Grimm smiles.

"Do you like being close to me?"

They nod fast before turning away, embarrassed. But then they put their hand back on Grimm's back to write. '_Try?_'

"Try what?" Grimm blinks. He's dizzy from being this close to them and still getting use to the the fact they are _talking_. It makes his heart race.

They struggle for words again. Their claw moves faster as they try and convey more, '_Mother would...kiss Father. When Father was sad_.'

"You wish to kiss me?"

They dip their head, not exactly a nod, but a shy action. Their fingers move more steadily, determined. '_Important. Like family._'

The Hollow Knight barely understands their own emotions but Grimm understands. They can't speak so they want to use the actions they've seen others do. Grimm leans forward tilting their chin up with his hand and kisses where their mouth would be softly. They push back, a bit too enthusiastically, and Grimm laughs again, grabbing their shoulders so he doesn't fall backwards.

"We'll work on it," his face is red and even without a mouth the kiss left him breathless. The Hollow Knight's shoulders shake just a bit too. They hold him close, hand pressed to his lower back and the movement of his claws spelling another word makes a shiver run down Grimm's spine.

'_Cute._'

"P-Pardon?!" They go to rewrite the word, "N-no, I felt it. I just...have never really been called _cute_."

They tilt their head to the side, nuzzling his cheek for the warmth. '_Warm_.' They write again, hands now lower on his back. Grimm can't help but shudder. He swallows.

"We...we should be getting back," his voice is low and he's suddenly acutely aware that he's in the Hollow Knight's lap and his body is hotter than it should be. Even more so, he wants desperately to kiss them again.

'_Did I go too far?_' It's the first full sentence they've written.

"No! No… I'm just…"

'_I want you._'

"W-what?" His head spins, afraid that he's drastically misunderstood something. They won't look at him but they reach under his thighs and pull him closer. Their hand moves then to the top of his thigh and Grimm inhales sharply. "Ambrosia… I…"

They rumble again, deeper. A growl. They nudge his head up, kissing him again and Grimm's breath catches in his throat. Their hand slides between his legs, thumb petting between his carapace plates. Grimm remembers the Pale King once complaining that the Hollow Knight was too curious, always sneaking off to read. It doesn't surprise him that they can feel arousal, more so that they wish to act upon it with _him_. It's hard for Grimm to get rid of his more childish tendencies when he's not fully molted and it's embarrassing. He would never be this self-conscious if his tail was gone. Quite the opposite, really, he would jumping at any possibility to fuck.

Grimm is abruptly jerked from his thoughts as the Hollow Knight's fingers stroke along his slit. A hiss leaves him and they pause, nudging him carefully. "It's...been a while…" He manages between pants. Their shoulders shake as they laugh silently. He's wet already and they easily slip a finger inside of him. Grimm's hips jerks and they tilt their head playfully. "D-don't stop…" Another growl vibrates their chest and they curl their finger inside of him. He lets out a low groan, claws digging into the Hollow Knight's shoulders. They move their finger inside of him slowly, helping ease his cock from the slit and allowing his cunt to fully open, before pushing in another digit. Grimm's head falls forward, pressed to their cold neck as he pants.

"Sneaking smutty novels while in training?" He asks, voice breathless. They thrust their fingers a bit rougher than before, pulling a grunt from him. "I-I'll take that as a yes…" He manages to tease, shaking slightly in pleasure. Without warning, they remove their fingers, eliciting a slight whine from Grimm as they pull him close and moving them both out of the water and onto the stone floor around the spring. They grip his thigh then, tugging his legs around their waist, and Grimm scrambles to close the distance.

But when his eyes fall to look between the Hollow Knight's legs, his eyes go wide.

"Oh…"

They tilt their head to the side, pausing.

"You are...well endowed…" his face flushes so hot he's afraid he might pass out. With them so close, he can feel the coldness of their own erection and it towers above his. Grimm has never considered himself small, but it is painfully obvious he is not exactly large either. He tears his eyes away from their cock when he sees their abdomen roll with a silent laugh. They trace words onto his thigh.

'_Would you like to stop?_' Formal and, with how slow and lazily they write, Grimm swears it's to tease him. It draws a growl from him.

"Gods, no," he pulls himself up to sit in their lap, reaching down to touch their member. It's cold and slick and they immediately jerk into his hand, almost startled by the sensation. "Ah, I am...your first, right?"

They nod slowly, pausing to consider words before they start to write, their claw moving quicker now. '_Never touched before._'

Grimm expected that. The mental abuse of forcing them not to feel probably involved a lot of them trying to forget even their natural instincts like arousal. It's flattering, though, that they are so easy with it around him. He strokes them softly, rubbing his thumb across their head and they shake in his grip. Grimm pushes closer, kissing their chest as he starts to move his fist around them. They cling to him, claws digging into his thigh. He's trying not to overwhelm them right away with the feeling. He peppers kisses up their neck and under their chin, pulling himself onto his knees to reach. They thrust their hips, chest rising and falling with silent gasps, and Grimm's own cock twitches as he watches them.

"I need you inside me," he says quickly, suddenly, kissing where their mouth would be roughly. They nod putting a hand on his hip to guide him. He holds their cock as he lines himself up and slowly inches himself down until he's fully impaled. They shudder, hand tight on his hip and Grimm nearly cums just the first thrust. He's light headed and panting. The Hollow Knight, though, does not seem keen on being patient and rolls their hips sharply. Grimm curses, reaching down between them to stroke his own cock.

Their fingers shake as they write. '_Tight._'

"You're just… very big," Grimm grinds out, raising himself up slightly before trusting back down. He moans, trying to keep an even pace as they roll their hips with him. The force of their shells colliding reverberates through them both and Grimm's cunt clenches.

'_Good?_'

"D-do you have to ask?" His voice is forced, making the question sound more intense than he meant. He tries to soothe it over with kisses to their jaw and they quiver, hand leaving his thigh to swat away his own hand around his cock and replace it with theirs. Grimm lets out a shaky growl, pace becoming uneven. They take over, moving their hips up in time with their hand and he opts to follow their pace. He rolls his hips forward with them, each movement hitting his g-spot.

His thighs are shaking and the Hollow Knight notices, nuzzling his neck. They give his cock a final squeeze before cupping his ass with their hand, helping him move. Grimm moans, low and needy, as they dig their claws into his shell.

"Ambrosia, I won't last long like this." They growl in reply, the void in them vibrating almost loud enough to hear from a distance. Their cock jerks inside of him at hearing their name and the reaction makes Grimm grind down harshly. He can feel their cold precum and he notices them slow slightly. "Cum inside me. Please, love, let me feel you."

They nod sharply, holding his hip down so he's flush against them as they simply roll their hips. It's a softer feeling, but it leaves Grimm feeling even fuller and each movement rubs his g-spot raw. It doesn't take long for him to cum with a groan, holding them tightly. His cock pinned between them releases hot seed that covers both of their stomachs and his cunt spasms. The Hollow Knight holds him still and the clenching milks their own orgasm. It's cold as they fill Grimm and he arches his back. The aftershocks fade after a moment, them both falling limp in each other's grip.

Finally, Grimm stands slowly, wincing as he does so. They lower their head in apology. He just reaches for their wrist to tug them up. They stumble nearly knocking both of them over and Grimm just sighs playfully. "Back into the water," he says, "You undid all the hard work I put into cleaning you."

Their hand finds the small of his back. '_No regrets._'


End file.
